A conventional automobile includes a heater (i.e., heating system) configured to selectively introduce warm air into a passenger compartment. As the warm air is circulated throughout the passenger compartment, the temperature within the passenger compartment is elevated to within a desired temperature range. Therefore, the occupants seated in passenger compartment of the automobile are kept comfortable.
The typical heater noted above includes, among other things, a control valve, a heater core, and a fan. The flow of heated coolant to the heater core is generally directed through flexible tubing or some other type of conduit. This heater loop is typically coupled in parallel to the radiator loop of the vehicle. As the engine is operated, the temperature of the coolant rises. The control valve is used to manage a flow of the heated coolant from the engine compartment to the heater core. The more heated coolant that the control valve allows to proceed to the heater core, the warmer the heater core becomes. Using the fan to move air over and around the warm heater core, the temperature within the passenger compartment is raised to within the desired temperature range.
Many of the control valves mentioned also include a bypass outlet. The bypass outlet permits the control valve to route the heated coolant back toward the radiator without the coolant passing through the heater core. Because the heater core is generally located within the passenger compartment, the ability of the control valve to utilize the bypass outlet is especially beneficial on a warm or hot day when additional heat in the passenger compartment is not desired. Using the bypass outlet, the control valve simply keeps the heated coolant in the engine compartment and away from the occupants of the vehicle. The bypass outlet also permits a pump moving the coolant through the heating system to continue operating even when heat is not called for.
To ensure that the entire passenger compartment is evenly heated or that certain areas of the passenger compartment are provided with additional heat, some newer and/or larger automobiles include more than one heater. For example, a large sport utility vehicle, van, or bus may include both a front heater and a rear heater. By using front and rear control valves and heater cores, the front heater manages the amount of heat expelled into a front portion of the passenger compartment while the rear heater controls the amount of heat expelled into a rear portion. To ensure that heat is not undesirably expelled into the passenger compartment, the front and rear heaters employ control valves so that occupants in both the front and rear of the passenger compartment are kept comfortable on hot and cold days.
In those applications where the ability to individually control the flow of the heated coolant to both front and rear heater cores in front and rear heaters is required, and where a bypass outlet is needed, the typical solution has been to employ some combination of control valves, tees, and other components coupled together by flexible interconnecting tubing. In at least one such application, the flow of heated coolant to the front heater core is controlled by a bypass valve and the flow of heated coolant to the rear heater core is controlled by a two-port on-off valve.
Unfortunately, each control valve, actuator used to manipulate the control valve, tree, connecting device, length of tubing connecting the various components together, and like heater components increases the overall cost of the multiple heater system. In addition, each of the components is subject to wear, failure, and/or leakage and, consequently, replacement. Having to replace worn, failed, or leaking components is a time consuming endeavor and will also increased system costs. Therefore, multiple heater systems with a large number of components are disfavored.
There exists, therefore, a need in the art for a flow control valve that simplifies the plumbing and packaging of multiple heater systems without sacrificing the ability to independently control the individual heaters. The invention provides such a control valve. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.